Perfluorinated propyl derivative compounds

ABSTRACT

Novel compositions include compounds of the formula: ##STR1## wherein the carbon rings are fully fluorinated.

This is a division of application Ser. No. 07/089,293, filed 8/25/87.

TECHNICAL FIELD

The present invention is related to the field of perfluorinated,alkyl-substituted, condensed ring compounds. More specifically, thepresent invention is directed to various propyl and methyl derivativesof decahydronaphthalene prepared from naphthalene, which former compoundis then fully fluorinated.

BACKGROUND OF THE PRIOR ART

Fluorinated carbon compounds are finding increasing utility in modernindustry, such as the electronics fabrication industry, and researchershave found heightened interest in fluorinated compounds for variousbiological and medical applications, such as synthetic blood anddiagnostic fluids.

Perfluorinated multiple condensed ring compounds have been known for asignificant period of time, such as perfluorophenanthrene as disclosedin U.S. Pat. No. 2,487,820. That patent makes a broad, general andunsupported disclosure that:

"Fused-ring aromatic hydrocarbons such as anthracene, naphthalene,phenanthrene and their substitution derivatives, can be fluorinatedreadily with the addition of fluorine atoms at the points ofunsaturation and, if desired, with the replacement of hydrogen in themolecule, and the production of saturated fluorine-containingcompounds."

Partially fluorinated compounds are exemplified by the1-methyl-(3,3,3-trifluoropropyl) naphthalene compounds disclosed in U.S.Pat. No. 4,396,785. These compounds are only marginally fluorinated andthe condensed carbon rings retain their unsaturated aromatic character.

The tertiary butyl derivatives of a single carbon ring, cyclohexene, isdisclosed in U.S. Pat. No. 4,453,028.

Perfluoro-2-methyldecahydronaphthalene has been reported to have beensynthesized from 2-methyl naphthalene using cobalt trifluoridefluorination technology as set forth in an article titled OrganicFluorides. Part V. Fluorination of Hydrocarbons With Cobalt Trifluoride,by R. N. Haszeldine and F. Smith appearing in Journal of ChemistrySociety (1950) pages 3617 to 3623.

The cobalt trifluoride fluorination of 1-methyl decahydronaphthalene toproduce perfluoro-1-methyl decahydronaphthalene has also been set forthin British Pat. No. 1,281,822. Fluorination of substituted naphthalenesis generally disclosed.

The basic technique for cobalt trifluoride fluorination is set forth inU.S. Pat. No. 2,631,170.

U.S. Pat. No. 3,775,489 is directed to the fluorination of variousaromatic carbon compounds of the naphthalene and anthracene class.

U.S. Pat. No. 3,786,324 discloses a utility for perfluorinatedhydrocarbons comprising dielectric fluids for capacitors. The compound1-trifluoromethylperfluorodecahydronaphthalene is mentioned as apotential dielectric fluid.

U.S. Pat. No. 4,106,557 describes a refrigeration apparatus utilizingvarious halogenated carbon refrigerants, including cyclic fluorinatedcarbon ethers.

U.S. Pat. No. 4,143,079 discloses a perfluorinated 1-methyl-4-isopropylcyclohexane. This material is recited to have utility as an artificialblood component.

U.S. Reissue Pat. No. 30,399 discloses a technique for solderingelectronic components in a mass production mode in the heated vapor of aboiling fluid wherein the vapor condenses on cold solder to be reflowedand the solder is melted by the heat of vaporization evolved during thecondensation of the adhering fluid vapor. This form of soldering isknown as vapor phase soldering, condensation soldering and variousreflow soldering nomenclatures. The criteria delineated for a heattransfer liquid for such soldering includes: a boiling point above themelting point of the solder wherein the boiling point is preferablysharply defined and dependent upon a single component rather thanmulticomponent materials, electrically non-conducting characteristics,vapors which are non-oxidizing, chemically stable and inert, non-toxic,non-inflammable and relatively denser than air, relatively high latentheat of vaporization, and degreasing properties. Fluorinatedpolyoxypropylene is a disclosed fluorocarbon suitable for heat transferliquid choice.

U.S. Pat. No. 4,549,686 describes vapor phase soldering usingperfluorotetradecahydrophenanthrene (perfluorophenanthrene).

British Pat. No. 785,641 discloses the fluorination of various carboncompounds with hydrogen fluoride wherein such compounds include benzene,toluene, anthracene and diamylnaphthalene. Retene, which is1-methyl-7-isopropyl phenanthrene, is also capable of the recitedfluorination treatment.

U.K. Patent Application No. 2110204A discloses variousperfluoro-alkyl-cyclohexane mixtures useful for vapor phase soldering inthe boiling range of 180° to 300° C. These materials are produced by thefluorination of narrow cut linear alkylbenzene compounds with cobalttrifluoride.

European Patent Application 0 194 009 discloses fluorochemicalcompositions comprising compounds in the form ofperfluoropolycycloalkane ring assemblies having (a) at least twoperfluorinated cyclohexane rings, (b) at least two perfluorinated fusedring systems, or (c) a combination of at least one perfluorinated fusedring system with at least one perfluorinated cyclohexane ring, eachperfluorinated ring or ring system being directly joined to anotherperfluorinated ring or fused ring system by a single bond. The rings mayhave certain substituent groups.

The prior art fluorination compounds have failed to provide a stable,inert perfluoro compound having a desirable sharp boiling point in theapproximate range of 215° C. which is most desirable for presentlyexisting vapor phase soldering utilities. In addition, the prior artcompounds suffer from various levels of susceptibility to heatdegradation to hydrogen fluoride and perfluoroisobutylene, as well ashaving undesirable fluorine utilizations due to significant levels ofaliphatic character. The present invention overcomes these shortcomings.

BRIEF SUMMARY OF THE INVENTION

The present invention is a perfluorinated compound of the formula:##STR2## wherein the carbon rings are fully fluorinated and R isselected from the group consisting of fluorine, --CF₃ or --CF(CF₃)₂.

One of the preferred species of the compounds of the present inventionis the perfluorodiisopropyl substituted decahydronaphthalene compound.Another preferred compound is the perfluorodiisopropyl substituteddecalin wherein the substitution is in the 2 and 7 positions. Yetanother of the preferred compounds of the present invention is theperfluoromethylisopropyl substituted decahydronaphthalene compound.Preferably, the perfluoromethyl radical is in the number 2 position onthe decahydronaphthalene ring. Alternately, the perfluoromethylsubstituent is in the number 1 position on the decahydronaphthalenering. Finally, one of the preferred species of the present invention isthe perfluorinated monoisopropyl substituted decahydronaphthalenecompound, particularly where the perfluorinated monoisopropylsubstituent is in the number 2 position.

The present invention is also directed to a method for utilizing suchcompounds wherein it comprises a method of soldering a component to besoldered by immersing a component in the vapor bath to melt the solder,and the component is then withdrawn from the vapor bath, the improvementcomprising that the vapor bath is composed substantially of compoundshaving the formula: ##STR3## wherein the carbon rings are fullyfluorinated and R is selected from the group consisting of fluorine,--CF₃ or --CF(CF₃)₂. The vapor bath can comprise mixtures of the recitedcompounds with other compounds such as perfluorophenanthrene.

DETAILED DESCRIPTION OF THE INVENTION

The various perfluorinated isopropyl derivatives of decalin, whichconstitute the subject matter of the present invention, are valuable asinert constant boiling fluids required by the electronic fabricationindustry for the manufacture and testing of various electroniccomponents. Fluids boiling in the temperature range of 150°-250° C. areof interest to the electronics industry for these applications.Currently, various suppliers of fluorinated fluids provide a series ofcompounds that meet the 150°-250° C. temperature range which are basedon, for example, perfluorinated tertiary amines. There is some questionon the stability of these materials at elevated temperatures. Oneconcern arises from incomplete fluorination, which results in residualhydrogen. These partially fluorinated compounds have been shown toundergo decomposition at elevated temperatures resulting in theformation of HF and perfluoroisobutylene.

Another class of compounds that are currently supplied to meet the needsfor a 150°-250° C. boiling fluid are based on perfluoropolyethers. Thesepolyethers are prepared by the oxidative polymerization oftetrafluoroethylene. To obtain the various boiling ranges, thepolyethers are distilled into different fractions. The final productdoes not constitute a single compound, but rather a mixture of molecularweight ranges. This results in a product, that with time will increasein boiling temperature as the lower molecular weight fractions areremoved by differential boil-off.

The compositions of the present invention constitute essentially singlecompounds having sharply defined boiling points which do not fractionateoff into various components through exposure to cycling from cooldown tohigh temperature utilization, such utilization as is characteristic ofvapor phase soldering fluid utility. For the sake of clarity thenumbering of the carbons on the decahydronaphthalene ring (fullysaturated naphthalene derivative) are set forth below. ##STR4##

The perfluoroisopropyldecahydronaphthalene compound of the presentinvention, which is preferably substituted at the number 2 position ofthe decahydronapthalene ring, has an empirical formula of C₁₃ F₂₄ and amolecular weight of 612. The material is a liquid at room temperaturewith a boiling point of approximately 200° C. The general structure ofthe compound of the present invention has been confirmed by ¹⁹ F NMR(nuclear magnetic resonance spectroscopy) and GC/MS (gaschromatography/mass spectroscopy). Typically, the feedstock to producesuch a perfluorinated compound is the hydrocarbondiisopropylnaphthalene, which can be prepared by the alkylation ofnaphthalene known techniques. The new composition of the presentinvention is substantially a perfluorinated analog of the abovehydrocarbon starting material wherein all aromatic character, hydrogenand one isopropyl group are removed as a result of the reaction process.All isomers and conformers of monoisopropylnaphthalene are representedby the perfluorinated compound of the present invention.

The perfluorodiisopropyldecahydronapthalene compound of the presentinvention, which is preferably substituted at the number 2 and number 7positions of the decahydronaphthalene ring, has an empirical formula ofC₁₆ F₃₀ and a molecular weight of 762. This material is liquid at roomtemperature with a boiling point of approximately 240° C. The generalstructure has been confirmed by ¹⁹ F NMR and GC/MS.

The feedstock for the production of this species of the compounds of thepresent invention is the hydrocarbon diisopropylnaphthalene which can beagain prepared by the alkylation of naphthalene by known techniques. Thecomposition is substantially a perfluorinated analog of the hydrocarbonstarting material with all aromatic character and hydrogen removed, butthe isopropyl substituents remaining intact. All isomers and conformersof diisopropylnaphthalene are represented by this invention.

The perfluoroisopropyl-1-methyldecahydronaphthaleneperfluoroisopropyl-2-methyldecahydronaphthalene species of theisopropyl, methyl-substituted decahydronaphthalene compounds of thepresent invention have an empirical formula of C₁₄ F₂₆ and a molecularweight of 662. The materials are liquid at room temperature with boilingpoints of approximately 219° C. Again, these structures have beenconfirmed by ¹⁹ F NMR and GC/MS. The feedstocks are hydrocarbonisopropylmethyl derivatives of naphthalene such asisopropyl-1-methylnaphthalene and isopropyl-2-methylnaphthalene whichare prepared by known alkylation techniques of naphthalene. Thecompositions of matter described immediately above are substantiallyperfluorinated analogs of the hydrocarbon starting materials with allaromatic character and hydrogen removed. All isomers and conformers ofisopropyl-methylnaphthalene are represented by this invention. Althoughthe number 1 position and the number 2 position methyl derivatives arepreferred examples of the present invention, it is appreciated thatother position isomers are included within the scope of thiscontemplated composition class.

All of these species of the compounds of the present invention haveutility for oxygen transport media for in vivo and in vitro use as puresubstances or mixtures or emulsions, as well as use as hydraulic fluids,lubricants, heat exchange or cooling fluids and other such applicationswhere chemical inertness and boiling point are the desired physical andchemical properties, most particularly vapor phase soldering. Various ofthe compounds have been tested as vapor phase soldering fluids. Thefluids were heated at reflux for an extended period of time and showedno evidence of decomposition, wherein a printed circuit board whichcontained a solder silk screen and a surface mounted device was immersedinto the reflux vapor area and the solder reflow occurred within 30seconds. This demonstrated successful and acceptable vapor phasesoldering utility.

At this time, the preparation and identification of the compounds of thepresent invention will be set forth in the following examples andtables.

EXAMPLE 1 (Notebook 7820-7297-17,18)

Twenty grams of di-isopropyl naphthalene was vaporized and charged to areactor containing sufficient cobalt trifluoride to carry out thereaction. The temperature of the cobalt trifluoride bed was set atapproximately 630°-650° F. Gaseous products from the reaction werecollected in traps held at 0° C. and -70° C. In run 17, 26.4 gms ofcrude fluorochemical and 26.3 gms of HF were collected. In run 18,performed under essentially identical conditions, 30.9 gms of crudefluorochemical and 37 gms of HF were produced.

EXAMPLE 2 (Notebook 7820-6832-92,94)

Crude fluorochemical of run 7297-17 was neutralized with 2M KOH andphase separated to give 21.3 gms of fluorinated material. By the sameprocedure, run 7297-18 resulted in 28.35 gms of fluorochemical product.Specific gravities of 2.04 gm/ml and 2.02 gm/ml respectively were foundindicating a perfluorinated product.

The neutralized material obtained above was combined and a total of27.38 gms of the fluorochemical was distilled. A pot reflux temperatureof 186° C. was shown with clear liquids distilled at pot temperaturesranging from 203° C. to 265° C. Yield of compound (1) [pot temperature203°-214° C.] was found to be 30.7%(perfluoromonoisopropyldecahydronaphthalene) and compound (2) [pot temp.221°-265° C.], 40.2% (perfluorodiisopropyldecahydronaphthalene.

EXAMPLE 3 (Notebook 7820-729-21)

A total of 62.3 gms of crude fluorochemical produced via the cobalttrifluoride fluorination of di-isopropyl naphthalene in previous runswas passed through the fluorination reactor at harsher conditions.Reactor temperatures of 800° F. were employed and a total of 41.7 gms ofproduct fluorochemical was collected.

EXAMPLE 4 (Notebook 7820-6832-97)

Crude fluorochemical obtained from run 7297-21-19) was distilled. Atotal of 39.39 gms was charged to the distillation apparatus and foundto have a pot reflux temperature of 149° C. Subsequent distillation wasdone resulting in a clear liquid with a specific gravity of 1.96-2.01gm/ml distilling at pot temperature range of 149°-214° C. and comprising75.3% of the material charged. This material is comprised substantiallyof compound (1), namely perfluoromonoisopropyldecahydronaphthalene,resultant from the removal of a single isopropyl group from the parentmolecule at the harsher fluorination conditions.

EXAMPLE 5 (Notebook 7820-8832-90, 91)

A total of 1884 grams of di-isopropyl naphthalene was fed to a pilotscale reactor (12" diameter×10' long) filled with sufficient cobalttrifluoride powder (˜375 lbs) to affect complete fluorination. Theorganic was introduced into the reactor by vaporization from a heatedpot (450° F. start-525° F. finish) purged with N₂ gas (1500 sccm).Reactor temperatures were held at 660° F. and the cobalt trifluoride bedwas continuously stirred in the reaction zone by an agitator running at2-3 rpm. Gases from the reactor were continually fed to a dust removaltrap and heat exchanger (30° F.) where crude fluorochemical product wascondensed.

EXAMPLE 6 (Notebook 7820-8220-66,67,68)

Crude fluorochemical product from the above and similar runs werecombined and further purified to remove HF and partially fluorinatedby-products. A total of 6000 grams of the purified material was thencharged to a distillation apparatus and distilled. A total of 1558 grams(26% of the charge) was found to be distilled at a head temperature of190°-205° C. This was later identified by 19^(F) NMR and GC/MS to besubstantially compound (1) namely,perfluoromonoisopropyldecahydronaphthalene. A further portion, 1267grams (21.1% of the charge) was found to distill at a head temperatureof 240°-245° C. This material was later identified by 19^(F) and GC/MSto be substantially compound (2) namely,perfluorodiisopropyldecahydronaphthalene.

                  TABLE 1                                                         ______________________________________                                        Analytical Characterizaton of                                                 Perfluorodiisopropyldecohydronapthalene                                       .sup.a NMR - .sup.19 F                                                        CF.sub.3         CF.sub.2   CF                                                -68 to -74       -90 to -150                                                                              -170 to -190                                      multiplet        multiplet  multiplet                                         ______________________________________                                        Relative F Atomic Ratio                                                       calculated                                                                            1.5          3.5        1.0                                           observed                                                                              1.4          3.9        1.0                                           .sup.b MASS SPECTRUM (m/e)                                                    calculated       612 (C.sub.13 F.sub.24)                                      observed         612 (C.sub.13 F.sub.24)                                      ______________________________________                                         .sup.a in CDCl.sub.3 /C.sub.2 Cl.sub.3 F.sub.3                                .sup.b electron ionization and/or chemical ionization with CH.sub.4      

                  TABLE 2                                                         ______________________________________                                        Analytical Characterization of                                                Perfluorodiisopropyldecohydronaphthaline                                      .sup.a NMR - .sup.19 F                                                        CF.sub.3         CF.sub.2   CF                                                -68 to -74       -90 to -150                                                                              -170 to -190                                      multiplet        multiplet  multiplet                                         ______________________________________                                        Relative F Atomic Ratio                                                       calculated                                                                            2.0          2.0        1.0                                           observed                                                                              2.1          2.3        1.0                                           .sup.b MASS SPECTRUM (m/e)                                                    calculated       762 (C.sub.16 F.sub.30)                                      observed         762 (C.sub.16 F.sub.30)                                      ______________________________________                                         .sup.a in CDCl.sub.3 /C.sub.2 Cl.sub.3 F.sub.3                                .sup.b electron ionization and/or chemical ionization with CH.sub.4      

EXAMPLE 7 (Notebook 7826-8876-80)

25.00 g of isopropyl-1-methylnaphthalene were charged to a samplecylinder and connected to an enclosed hotplate operating at 290° C. Theisopropyl-1-methyl naphthalene was fed into the hotplate by a meteringpump at a rate of 10.3 g/hr into a 15.5 sccm nitrogen stream. Theorganic/nitrogen stream was carried into a cobalt trifluoride reactor 10cm in diameter and 60 cm long containing approximately 3000 g cobalttrifluoride. The reactor was heated with a three zone furnace operatingat 285°, 285° and 315° C., respectively. The isopropyl-1-methylnaphthalene feed was subsequently converted to a perfluorochemical inthe reactor and was collected in a trap held at 25° C. 67.7 g of a lightyellow liquid was collected. Additional material was produced undersimilar reactor conditions.

EXAMPLE 8 (Notebook 7826-8490-51)

92.5 g of the combined cobalt trifluoride products were charged to a 40ml stainless steel sample cylinder for a direct fluorination clean-upstep. A fluorine/nitrogen gas mixture increasing to 100% fluorine withtime was sparged into the liquid at 25° C. and 150° C. Approximately 1.0g of elemental fluorine was added into the crude perfluorochemicalmixture.

EXAMPLE 9 (Notebook 7826-8490-52)

59.4 g of the directly fluorinated product from above was distilled in amicro spinning band still. A fraction boiling at 219° C. was collectedwhich represented 43.3% (by GC) of the original charge. Thefluorochemical was identified as fluoro,isopropyl-1-methyldecahydronaphthalene. Analytical information is shownin Table 3.

EXAMPLE 10 (Notebook 7826-9497-5)

25.00 g of isopropyl-2-methylnaphthalene were charged to a samplecylinder and connected to an enclosed hotplate operating at 300° C. Theisopropyl-2-methylnaphthalene was fed onto the hotplate by a meteringpump at a rate of 9.7 g/hr into a 15.5 sccm nitrogen stream. Theorganic/nitrogen stream was carried into a cobalt trifluoride reactor 10cm in diameter and 60 cm long containing approximately 3000 g cobalttrifluoride. The reactor was heated with a furnace operating at 300° C.The isopropyl-2-methylnaphthalene feed was subsequently converted to52.0 g of perfluoro, isopropyl-2-methyldecahydronaphthalene asidentified by GC/MS [calculated m/e 662 (C₁₄ F₂₆); observed m/e 662 (C₁₄F₂₆)].

                  TABLE 3                                                         ______________________________________                                        Analytical Characterization of Perfluoro,                                     isopropyl-1-melhefdeohydronaphthalene                                         .sup.a NMR - .sup.19 F                                                        CF.sub.3        CF.sub.2     CF                                               -64 to -75.sup.b                                                                              -100 to -145.sup.b                                                                         -165 to -190.sup.b                               multiplet       multiplet    multiplet                                        ______________________________________                                        Relative F Atomic Ratio                                                       calculated                                                                            1.8         2.4          1.0                                          observed                                                                              1.6         2.6          1.0                                          .sup.c MASS SPECTRUM (m/e)                                                    calculated      662 (C.sub.14 F.sub.26)                                       observed        643 (C.sub.14 F.sub.26 -F)                                    ______________________________________                                         .sup.a in CDCl.sub.3 /CCl.sub.3 F                                             .sup.b ppm from CCl.sub.3 F                                                   .sup.c electron ionization and/or chemical ionization with CH.sub.4      

EXAMPLE 11 (Notebook 7826-8490-102)

A glass vapor phase soldering apparatus consisting of a 100 ml flaskconnected to a condenser was used to demonstrate vapor phase solderingwith perfluoro, isopropyl methyl decahydronaphthalene. A solder pasteconsisting of 96.5% tin and 3.5% silver was used to coat a printedcircuit board. A surface mount device was positioned on the solder pasteand the entire assembly was immersed in perfluoro, isopropyl methyldecahydronaphthalene which had been heated to reflux temperature. Solderreflow was observed to occur in approximately 26 seconds. Upon removalof the circuit assemble, no fluorochemical residue was observed, butclean substantial reflow of the solder was observed and the assemblycomprising the surface mounted device and printed circuit board werefirmly affixed by the operation of the solder.

These compounds of the present invention have particularly desirableutility in a method of soldering a component to be soldered by immersinga component in the vapor bath to melt the solder, and the component isthen withdrawn from the vapor bath, the improvement comprising that thevapor bath is composed substantially of compounds having the formula:##STR5## wherein the carbon rings are fully fluorinated and R isselected from the group consisting of fluorine, --CF₃ or --CF(CF₃)₂. Thecompounds can be mixed with one another or other compounds such asperfluorophenanthrene. Vapor phase soldering is described in U.S. Pat.No. 30,399 and U.S. Pat. 4,549,686, both of which are incorporatedherein by reference.

The compounds of the present invention succeed in overcoming thedrawbacks of various of the compounds of the prior art, particularly forutility in vapor phase soldering fluid use. The compounds of the presentinvention exhibit all of the desired attributes of a vapor phasesoldering fluid as identified in Reissue Pat. No. 30,399 describedabove. Included in these attributes which the compounds in the presentinvention exhibit are: low toxicity, chemical inertness, lack offlammability, appropriate dielectric characteristics, degreasingproperties, sharply defined boiling point, a vapor denser than air andrelatively high latent heat of vaporization. Specifically, thesecompounds have low potential for evolution of HF andperfluoroisobutylene when subjected to long term cyclic heating andcooling typical of vapor phase soldering use.

The present invention has been set forth with regard to various specificexamples and embodiments of the invention. However, the scope of theinvention should be ascertained from the claims which follow.

We claim:
 1. The perfluorinated compounds of the formula: ##STR6##wherein the carbon rings are fully fluorinated.
 2. The perfluorinatedcompounds of claim 1 having the formula: ##STR7## wherein the carbonrings are fully fluorinated.
 3. The perfluorinated compounds of claim 1having the formula: ##STR8## wherein the carbon rings are fullyfluorinated.